pycameleon 0.2.4

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Pycameleon

A python binding for cameleon, a rust crate to interact with U3V (USB 3 Vision) camera that implement GenICam.

⚠️ Work in Progress
This project is currently under active development. Features are being added, and APIs may change as we improve the design.

We welcome new contributors! If you want to help, here’s how you can get involved:

Your contributions, whether code, documentation, or ideas are highly appreciated!

Instalation

PyPI (Recommended)

This package is available in PyPI.

pip install pycameleon

Build from source

Build dependencies:

• Rust/Cargo toolchain installed
• maturin pip install maturin/pipx install maturin
• libusb header (See cameleon FAQ)

First install maturin using pip or pipx or other package manager.

pip install maturin

Then run the following to install the package into the current environment.

maturin develop

Linux

By default, many devices are only accessible to root and need udev rules for non root users to access.

First use lsusb to list vendor and product id ID vendor_id:product_id.

Then, create an udev rule file at /etc/udev/rules.d/, for example /dev/udev/rules.d/99-u3v.rules

Choose and change vendor and product id with your own.

# Example: USB with vendor Id 2676 and product id 5678
SUBSYSTEM=="usb", ATTRS{idVendor}=="2676", ATTR{idProduct}=="5678", MODE:="0666", TAG+="uaccess", TAG+="udev-acl"
# Example: USB with vendor Id 2676 with any product id
SUBSYSTEM=="usb", ATTRS{idVendor}=="1234", MODE:="0666", TAG+="uaccess", TAG+="udev-acl"

If the framerate is low, you may need to increase usbfs_memory_mb limit. By default, USB-FS on Linux systems only allows 16 MB of buffer memory for all USB devices. This is quite low for high-resolution image streaming. We recommend you to set the value to 1000MB. You could set the value as following:

echo 1000 > /sys/module/usbcore/parameters/usbfs_memory_mb

Windows

For Windows, driver supported by libusb like WinUSB is required.

In most case, Zadig is recommended as an Automated Driver Installer GUI application.

NOTE: Make sure to install a driver to a composite device not to its child devices. To do this, you need to list all devices connected to the host computer with zadig like below.

MacOS

MacOS should have out of box support after installing the pip package, for building from source, the libusb package is available in homebrew.

Quick Usage

import pycameleon


# List all available cameras
available_camera = pycameleon.enumerate_cameras()

# Get the first U3V camera
cam = available_camera[0]

# Open the device in USB level
cam.open()

# Load the GenApi context and return it as XML string
gen_api_context = cam.load_context_from_camera()

# As a alternative, you can load gen api context dumped previously as `.load_context_from_camera()` can fail if already streaming or in invalid state.
# cam.load_context_from_xml(read_xml_to_string(str(cam)))


# After loading the context, we can read/write nodes and execute commands.
# Depending on the camera model, some nodes may not be available.
# Check the dumped GenApi XML for available nodes.

# Reset the device, need to enumerate it again and open from scratch after this.
# cam.execute("DeviceReset")

# Tell the camera to use Mono8 pixel format
cam.write_enum_as_str("PixelFormat", "Mono8")

# Start streaming and prepare a payload buffer for 1 channel.
payload = cam.start_streaming(1)

# Receive a single image from camera.
img, info = cam.receive_raw(payload)

# `img`` is an numpy array with type uint8, it's the raw byte array received from camera.

# `info` contain image information such as width, height and pixel format.


# At the end, close the camera to release USB handler.
cam.close()